A bicycle wheel contains two sets of bearings inside its hub. The hub and axle are the centre of the wheel, and the bearings allow the hub to rotate smoothly around the axle. Each set of bearings is contained inside a sealed cartridge. When replacing the bearings, the cartridge as a whole is replaced. Before the bearings can be accessed the appropriate wheel must first be removed from the bicycle. If removing rear wheel bearings, first follow the steps for cassette removal. A front wheel does not contain a cassette.
Set the wheel upright on the ground between your feet. Position the wheel so that the cassette is facing away from you.
Insert a bicycle free wheel removal tool through the centre of the cassette.
Attach the chain-end of a chain whip to any one of the cogs contained within the cassette cluster. Hold the chain whip handle between the two- and three-o'clock positions.
Adjust a crescent wrench to fit onto the flat portion of the free wheel removal tool. Hold the handle of the crescent wrench at the nine-o'clock position.
Rotate the crescent wrench handle downward, loosening the cassette lock ring. Remove all tools, and unthread the cassette lock ring with your fingers.
Separate the cassette from the side of the wheel.
Use a flat head screwdriver to pry off any rubber seals protecting the cone and locknut on the sides of the axle. These seals may be located on both sides.
Lay the wheel on its right, drive-side.
Slide the appropriate size cone wrench onto the flat portion of the left side cone. A cone will have two flat sides and will be located directly beside a locknut.
Attach the crescent wrench to the locknut. Turn the cone wrench and locknut counterclockwise against the cone.
Unthread the locknut and cone fully from the side of the axle. Lift the wheel carefully and slide the axle from the right, drive-side of the wheel.
Remove both bearing cartridges. There will be one cartridge on each side of the wheel. The cartridges resemble a small, metallic doughnut with a rubber seal.